#include <fstream>

using namespace std;

int t[100000], n, m, a[100000][100000], s[100000];

ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");

void DF_E(int nod)
{
    fout << nod << " ";
    for(int i = 1; i <= n; i++)
    if(a[nod][i])
        if(t[nod] != i && t[i] != nod)
        {
            a[nod][i] = a[i][nod] = 0;
            DF_E(i);
        }
    for(int i = 1; i <= n; i++)
        if(a[nod][i])
        {
            a[nod][i] = a[i][nod] = 0;
            DF_E(i);
        }
}

void DF(int nod)
{
    s[nod] = 1;

    for(int i = 1; i <= n; i++)
        if(!s[i] && a[nod][i] == 1)
        {
            t[i] = nod;
            DF(i);
        }
}

int main()
{
    int x, y;
    fin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        fin >> x >> y;
        a[x][y] = a[y][x] =1;
    }
    DF(1);
    DF_E(1);

    fin.close();
    fout.close();
    return 0;
}